Alloy



Patented Dec. 29, 1 942.

ALLOY Samuel Turkus, East range, N. 5., assignor to American Smclting and Refining Company, New York, N. Y., a corporation of New Jersey No Drawing. Application February 13, 1942; Serial No. 430,804

1 Claim. (Ci. 75-106) This invention relates to lead alloys and more particularly to lead-tin-bismuth-sllver alloys. The alloys of the present invention are especial- 1y useful as solders but they may be utilized for other purposes where it is desired to employ an alloy having the physical characteristics of the metals hereinafter described.

Alloyscomposed 01' lead-tin-bismuth and leadsilver have been compounded and used as solders, but the physical properties of these alloys 'tion will become apparent as the description proceeds.

In the following table there is listed some of the salient physical characteristics of the alloys Some physical properties of soft solders of my invention which have been determined.

For comparison, corresponding test values are given for some conventional tin-lead and silverlead solders. In each instance carefully standardized testing technique was employed in obtaining the results shown:

TABLE Composition, per cent Tensile Join I.

I mum! strength strength Spread 0C (cast; (sham? oft-151m.

' poum s poum s sr in. Pb Sn m sh per sq. in. per sq. in. I

60 40 238 5660 0270 1.30 97, 6 2. 5 304 4080 3740 0. i0 95 5 375 4.015 4340 0. 90 l() 208 4850 4000 0. 27 30 20 275 4040 5600 0 37 30 257 5300 5770 0. 83 78. 5 l5 1. 5 5 l 204 4000 5310 0. 47 77.5 15 I. 5 6 l 1 258 8000 5000 0. 20 74. 85 20 l. 5 3 0. 5 l 258 8120 5380 0. 39

Nora-Bond and spread tests were made on copper sheet. 'iensiie tests were made on chill cast strips of the alloys.

1 Determined in this investigation from cooling curves.

are not comparable with the ordinary lead-tin solders. I have discovered, however, after considerable experimentation, that a novel and highly useful alloy can be made composed of lead,

tin, bismuth and silver. Using certain proportionate amounts of these elements, alloys are formed which are particularly valuable as sol- 53 sessed by said base alloy.

One of the principal objects of the present invention is to provide a lead alloy solder which is comparable in working and physical proper,- tles with the conventional lead-tin solders but contains decidedly lesspercentage amounts of tin.

As shown in the table, the quaternary alloys of lead-tin-bismuth and silver may contain small Other objects and advantages of this invenamounts of antimony. From 0.25% to 3% of antimony may be present or added, particularly where high tensile strength is desired. A large number of specific alloy compositions comprising lead, tin, bismuth and silver may be made. depending upon the use for which the alloy is intended, by varying the percentage amounts of the constituents. An example of an alloy which I have found to be especially valuble asolder contains 78.5% lead, 15% tin, 5% bismuth and 1.5% silver.

Alloys containing 15% tin, 5% bismuth, 1.5% silver, 1% antimony and balance lead or 20% tin, 3% bismuth, 1.5% silver, 0.5% antimony and balance lead, have liquidus temperatures slightly higher than that of 40-60 tin-lead solders, markedlyhigher tensile strength and a' bond strength of approximately The spreading properties are, however, somewhat inferior to the 40-60 tin-lead alloys but superior to the binary leadsilver solders. By appropriate adjustment of the tin, bismuth and silver contents, fairly wide ranges of melting points and other properties can be obtained. Cans soldered on automatic machines using these lead-tin-bismuth-sllver alloys passed all standard tests for 40-60 and 50-50 tin-lead solders.

The amount of tin may be reduced to 10% but the melting point range is increased and the melted solder is slightly less fluid. While the preferred alloy composition is as stated, I have found that percentage amounts of the ingredients may be varied within a fairly broad range. For example. the alloy composition may comprise from 5% to 40% tin, 1% to 10% bismuth, 0.5% to 5.0% silver with the balance of the composition being lead.

From-the data given, it will be readily apparent that the alloys of this invention possess and exhibit properties which make them suitable for various uses other than solders, and such other uses are contemplated within the scope of this invention as defined by the appended claim.

What is claimed is:

A relatively low melting point solder comprising an alloy composition which consists principally of lead, tin, bismuth and silver, said constituents approximating from 5% to 40% tin, 1% to 10% bismuth, 0.5% to 5.0% silver, with the substantially all oi lead.

SAMUEL TURKUS. 

